Driver core: change add_uevent_var to use a struct
This changes the uevent buffer functions to use a struct instead of a long list of parameters. It does no longer require the caller to do the proper buffer termination and size accounting, which is currently wrong in some places. It fixes a known bug where parts of the uevent environment are overwritten because of wrong index calculations. Many thanks to Mathieu Desnoyers for finding bugs and improving the error handling. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Kay Sievers
committed by
Greg Kroah-Hartman
Greg Kroah-Hartman
parent
8380770c84
commit
7eff2e7a8b
@ -22,8 +22,6 @@
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#include <linux/kobject.h>
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#include <net/sock.h>
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#define BUFFER_SIZE 2048 /* buffer for the variables */
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#define NUM_ENVP 32 /* number of env pointers */
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/* the strings here must match the enum in include/linux/kobject.h */
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const char *kobject_actions[] = {
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@ -54,31 +52,21 @@ static struct sock *uevent_sock;
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* corresponding error when it fails.
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*/
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int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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char *envp_ext[])
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char *envp_ext[])
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{
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char **envp;
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char *buffer;
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char *scratch;
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const char *action_string;
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struct kobj_uevent_env *env;
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const char *action_string = kobject_actions[action];
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const char *devpath = NULL;
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const char *subsystem;
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struct kobject *top_kobj;
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struct kset *kset;
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struct kset_uevent_ops *uevent_ops;
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u64 seq;
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char *seq_buff;
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int i = 0;
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int retval = 0;
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int j;
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pr_debug("%s\n", __FUNCTION__);
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action_string = kobject_actions[action];
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if (!action_string) {
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pr_debug("kobject attempted to send uevent without action_string!\n");
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return -EINVAL;
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}
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/* search the kset we belong to */
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top_kobj = kobj;
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while (!top_kobj->kset && top_kobj->parent) {
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@ -92,7 +80,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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kset = top_kobj->kset;
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uevent_ops = kset->uevent_ops;
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/* skip the event, if the filter returns zero. */
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/* skip the event, if the filter returns zero. */
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if (uevent_ops && uevent_ops->filter)
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if (!uevent_ops->filter(kset, kobj)) {
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pr_debug("kobject filter function caused the event to drop!\n");
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@ -109,18 +97,11 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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return 0;
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}
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/* environment index */
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envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
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if (!envp)
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/* environment buffer */
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env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
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if (!env)
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return -ENOMEM;
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/* environment values */
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buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
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if (!buffer) {
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retval = -ENOMEM;
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goto exit;
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}
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/* complete object path */
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devpath = kobject_get_path(kobj, GFP_KERNEL);
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if (!devpath) {
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@ -128,29 +109,29 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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goto exit;
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}
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/* event environemnt for helper process only */
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envp[i++] = "HOME=/";
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envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
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/* default keys */
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scratch = buffer;
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envp [i++] = scratch;
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scratch += sprintf(scratch, "ACTION=%s", action_string) + 1;
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envp [i++] = scratch;
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scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1;
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envp [i++] = scratch;
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scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1;
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for (j = 0; envp_ext && envp_ext[j]; j++)
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envp[i++] = envp_ext[j];
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/* just reserve the space, overwrite it after kset call has returned */
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envp[i++] = seq_buff = scratch;
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scratch += strlen("SEQNUM=18446744073709551616") + 1;
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retval = add_uevent_var(env, "ACTION=%s", action_string);
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if (retval)
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goto exit;
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retval = add_uevent_var(env, "DEVPATH=%s", devpath);
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if (retval)
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goto exit;
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retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem);
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if (retval)
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goto exit;
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/* keys passed in from the caller */
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if (envp_ext) {
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for (i = 0; envp_ext[i]; i++) {
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retval = add_uevent_var(env, envp_ext[i]);
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if (retval)
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goto exit;
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}
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}
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/* let the kset specific function add its stuff */
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if (uevent_ops && uevent_ops->uevent) {
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retval = uevent_ops->uevent(kset, kobj,
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&envp[i], NUM_ENVP - i, scratch,
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BUFFER_SIZE - (scratch - buffer));
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retval = uevent_ops->uevent(kset, kobj, env);
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if (retval) {
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pr_debug ("%s - uevent() returned %d\n",
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__FUNCTION__, retval);
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@ -158,11 +139,13 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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}
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}
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/* we will send an event, request a new sequence number */
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/* we will send an event, so request a new sequence number */
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spin_lock(&sequence_lock);
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seq = ++uevent_seqnum;
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spin_unlock(&sequence_lock);
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sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq);
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retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq);
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if (retval)
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goto exit;
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#if defined(CONFIG_NET)
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/* send netlink message */
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@ -172,17 +155,19 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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/* allocate message with the maximum possible size */
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len = strlen(action_string) + strlen(devpath) + 2;
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skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL);
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skb = alloc_skb(len + env->buflen, GFP_KERNEL);
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if (skb) {
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char *scratch;
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/* add header */
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scratch = skb_put(skb, len);
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sprintf(scratch, "%s@%s", action_string, devpath);
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/* copy keys to our continuous event payload buffer */
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for (i = 2; envp[i]; i++) {
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len = strlen(envp[i]) + 1;
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for (i = 0; i < env->envp_idx; i++) {
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len = strlen(env->envp[i]) + 1;
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scratch = skb_put(skb, len);
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strcpy(scratch, envp[i]);
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strcpy(scratch, env->envp[i]);
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}
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NETLINK_CB(skb).dst_group = 1;
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@ -198,13 +183,19 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
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argv [0] = uevent_helper;
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argv [1] = (char *)subsystem;
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argv [2] = NULL;
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call_usermodehelper (argv[0], argv, envp, UMH_WAIT_EXEC);
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retval = add_uevent_var(env, "HOME=/");
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if (retval)
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goto exit;
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retval = add_uevent_var(env, "PATH=/sbin:/bin:/usr/sbin:/usr/bin");
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if (retval)
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goto exit;
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call_usermodehelper (argv[0], argv, env->envp, UMH_WAIT_EXEC);
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}
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exit:
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kfree(devpath);
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kfree(buffer);
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kfree(envp);
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kfree(env);
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return retval;
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}
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@ -227,52 +218,38 @@ int kobject_uevent(struct kobject *kobj, enum kobject_action action)
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EXPORT_SYMBOL_GPL(kobject_uevent);
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/**
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* add_uevent_var - helper for creating event variables
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* @envp: Pointer to table of environment variables, as passed into
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* uevent() method.
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* @num_envp: Number of environment variable slots available, as
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* passed into uevent() method.
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* @cur_index: Pointer to current index into @envp. It should be
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* initialized to 0 before the first call to add_uevent_var(),
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* and will be incremented on success.
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* @buffer: Pointer to buffer for environment variables, as passed
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* into uevent() method.
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* @buffer_size: Length of @buffer, as passed into uevent() method.
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* @cur_len: Pointer to current length of space used in @buffer.
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* Should be initialized to 0 before the first call to
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* add_uevent_var(), and will be incremented on success.
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* @format: Format for creating environment variable (of the form
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* "XXX=%x") for snprintf().
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* add_uevent_var - add key value string to the environment buffer
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* @env: environment buffer structure
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* @format: printf format for the key=value pair
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*
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* Returns 0 if environment variable was added successfully or -ENOMEM
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* if no space was available.
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*/
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int add_uevent_var(char **envp, int num_envp, int *cur_index,
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char *buffer, int buffer_size, int *cur_len,
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const char *format, ...)
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int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
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{
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va_list args;
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int len;
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/*
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* We check against num_envp - 1 to make sure there is at
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* least one slot left after we return, since kobject_uevent()
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* needs to set the last slot to NULL.
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*/
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if (*cur_index >= num_envp - 1)
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if (env->envp_idx >= ARRAY_SIZE(env->envp)) {
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printk(KERN_ERR "add_uevent_var: too many keys\n");
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WARN_ON(1);
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return -ENOMEM;
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envp[*cur_index] = buffer + *cur_len;
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}
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va_start(args, format);
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*cur_len += vsnprintf(envp[*cur_index],
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max(buffer_size - *cur_len, 0),
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format, args) + 1;
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len = vsnprintf(&env->buf[env->buflen],
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sizeof(env->buf) - env->buflen,
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format, args);
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va_end(args);
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if (*cur_len > buffer_size)
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if (len >= (sizeof(env->buf) - env->buflen)) {
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printk(KERN_ERR "add_uevent_var: buffer size too small\n");
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WARN_ON(1);
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return -ENOMEM;
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}
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(*cur_index)++;
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env->envp[env->envp_idx++] = &env->buf[env->buflen];
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env->buflen += len + 1;
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return 0;
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}
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EXPORT_SYMBOL_GPL(add_uevent_var);
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